Horseshoe

ABSTRACT

A two-part horseshoe consists of a channel-shaped upper part (10) to be nailed to the horse&#39;s hoof and an exchangeable lower part (20), which is made of an elastic material and has a ridge member (22) that can be pressed up into the channel (15) of the upper part. The side walls of the channel have a plurality of inwardly extending projections (16) with end faces directed toward the channel bottom (11), and the side walls of the ridge member are formed with corresponding recesses (25) which the projections snap into when the ridge member is pressed into position in the channel. In the front portion of the lower part there is embedded a metal insert (40) having partly a locking hook (43) to cooperate with a corresponding locking hook (19) on the front side wall (13) of the upper part, partly a plate-shaped member (41) forming a toe wear bracket on the underside of the lower part. When the projections (16) of the upper part are brought into engagement with the recesses (25) in the lower part they prevent such displacement of the lower part with respect to the upper part as is required to release the locking hooks from the locking engagement. Thus, the lower part cannot be loosened by the influences which occur in use; it can only be removed in a specific manner, viz. progressively from the rear ends and starting with the use of a hoof cleaner or a similar object as a crowbar or lever.

The invention relates to a horseshoe including an elastic lower partthat reduces the load on the bones and muscles of the horse by itsspring effect, in particular when the horse strikes a hard surface.

The U.S. Pat. Spec. No. 610 804 discloses a two-part horseshoe with anelastic lower part, where the sides of the ridge member of this part areformed with tongues or flanges to protrude into corresponding grooves inthe side walls of the upper part. The tongues or the flanges and thegrooves have a rectangular cross-section so that the lower part must beapplied by inserting its ridge member longitudinally into the upperpart. This requires a very loose fit between the two parts, which makesit necessary to retain the lower part by means of transverse rivetsextended through holes in the side walls of the upper part and into theridge member of the lower part. The use of such horseshoes involves therisk that the retaining rivets and then the lower part fall off.

The Swedish Pat. Spec. No. 8 597 discloses a horseshoe comprising twometallic parts, a fixed and an exchangeable one, with an intermediatepacking. The lower part is detachably attached to the upper part bymeans of a locking pin which is slidably mounted on the front of theupper part and is spring loaded to engage a hole in the lower part.Fixed, cooperating engagement means are provided at the rear ends of thetwo parts.

The U.S. Pat. Spec. No. 660 788 discloses a two-part horseshoe with anelastic lower part, where the side walls of the channel-shaped upperpart have spaced, inwardly directed hooks acting as barbs to retain thelower part after the lower part has been pressed past the hooks into theupper part. Such securing is insufficient to withstand the influencesoccurring in practice.

The object of the invention is to provide a horseshoe of the presenttype whose lower part is easy to exchange without using any tool otherthan e.g. a hoof cleaner, but which is nevertheless firm in positioneven under extremely severe conditions of use.

This object is achieved by providing cooperating projections andrecesses on the upper part of the horseshoe, which is attached to thehorse's hoof, and the exchangeable lower part, which consists of anelastic material, in which the projections are provided on the upperpart and have an inclined, downwardly extending face and the recessesare formed in the ridge member of the lower part. An insert of a hard,strong material is embedded in the front or toe portion of the lowerpart and this insert and the upper part are formed with cooperatinglocking means which upon being engaged with each other can be fixed inlocking engagement by causing the cooperating projections and recessesto engage each other by impression of the lower part into the upperpart. The projections and the recesses, in addition to keeping the ridgemember of the lower part in position on the upper part at the points,viz. the rearwardly directed forks of the shoe, where the detachingforces are relatively small, also serve the important function ofkeeping the locking means lockingly engaged at the front of shoe wherethe greatest forces are applied.

To further enhance the reliability of securing, the parts of thehorseshoe together, the insert has a portion which, in the assembledhorseshoe, protrudes upwardly in front of the rear side wall of theupper part. The rear side wall of the upper part prevents the upwardlyextending portion of the insert from moving more than just slightlyrearwards under the action of forces which urge the elastic lower partrearwards with respect to the upper part, and which, in some forms oflocking means, might tend to cancel the locking engagement.

Preferably, the locking means are formed by a first locking hookextending rearwardly from the front portion of the front side wall ofthe upper part, and a second locking hook so disposed on the insert thatupon displacement of the lower part with respect to the upper part, thetwo locking hooks can be caused to overlap each other with the lockinghook of the insert disposed closest to the channel bottom of the upperpart. This has the advantage that the locking means can only bedisengaged when the lower part is shifted longitudinally with respect tothe upper part, and such movement is effectively prevented not only bythe cooperating recesses and projections, but also by the considerablefriction between the tightly fitting lower part ridge member and theupper part.

An important advantage in the use of an exchangeable lower part is thatthe rider may have a range of various lower parts which are eachspecially adapted to special conditions. Some lower parts may thus havemoulded spikes for use on icy surfaces or bosses for use on softsurfaces. Lower parts for use on asphalt or a similar surface mayexpediently have a smooth underside without protruding parts.

The invention will be explained more fully below with reference to thedrawing, in which

FIGS. 1 and 2 are oblique bottom views of an embodiment of thehorseshoe,

FIGS. 3 and 4 are oblique top and oblique bottom views, respectively, ofthe lower part,

FIG. 5 shows a metallic insert incorporated in the lower part,

FIGS. 6 and 7 are oblique top and oblique bottom views, respectively, ofanother embodiment of the horseshoe of the invention,

FIGS. 8 and 9 are oblique top and oblique bottom views, respectively, ofthe lower part for this horseshoe,

FIG. 10 shows a metallic insert incorporated in the latter lower part,

FIG. 11 is a side view of the rear end portion of a modified embodimentof the lower part,

FIG. 12 is a section taken along the line XII--XII in FIG. 11,

FIGS. 13 and 14 are cross-sectional views of the head end of twodifferent embodiments of nails of the invention and lower parts forreceiving said nails,

FIG. 15 is a side view of a tool for use in the manufacture of an upperpart like the one shown in FIGS. 1 and 2 or 6 and 7 while performing amoulding operation, which is part of the method of the invention, onsuch an upper part,

FIG. 16 is an end view of the same tool,

FIG. 17 shows another tool in the process of a final moulding operation,which forms another part of the method of the invention, on the upperpart, and

FIG. 18 is a cross-section of the fork of the upper part thus treated,

FIG. 19 shows a modified embodiment of the insert,

FIGS. 20 and 21 are vertical sections of an insert like the one shown inFIG. 19 and with a calk placed therein, with and without a wear plate,respectively,

FIG. 22 is a vertical section of an insert with a welded anchoringangle, and

FIG. 23 shows an upper part with a special arrangement of the nailholes.

The upper part shown in FIGS. 1 and 2 is generally designated by 10 andis made of metal by drawing and forms a channel 15 with a bottom wall11, an inner side wall 12 and an outer side wall 13; these two sidewalls merge into each other at the ends and are disposed substantiallyperpendicularly to the bottom wall 11. The bottom wall is formed withnail holes 14, and the edges of the side walls 12 and 13 are formed witha plurality of hooks 16 which are disposed in spaced relationship on therearwardly directed forks of the shoe and protrude into the channel 15,said hooks 16 having end faces 16a which face the bottom wall 11. Thetop side of each hook curves from the outer side of the side wallinwardly toward the hook edge. This facilitates the pressing operationof the ridge member of the lower part into the upper part as describedbelow. The front portion of the upper part has welded to it a triangularplate 17 which forms a so-called toe-clip, and the front portion of theouter side wall 13 is formed with a rectangular opening or recess 18.The lower part shown in FIGS. 3 and 4 is generally designated by 20 andis moulded of a suitable, elastic and wear-resistant plastics material,such as polyurethane, and consists of an outer member 21 and a ridgemember 22 intended to be inserted into the channel 15 of the upper part20. This ridge member is somewhat narrower than the outer member 21 soas to provide a shoulder 23 at the transition between the two parts;this shoulder 23 extends all the way round along the lower part andengages, in the finished shoe, the lower edge of the side walls 11 ofthe upper part 10. The advantage of this construction is that thegreatest possible amount of material of the ridge member between thehook engagement face of the individual recess and the top side of theridge member is available for retaining the lower part in the upperpart. The top side of the ridge member 22 is formed with a plurality ofrecesses 24 to receive the heads of the nails by which the upper part 10is nailed to the horse's hoof. The side walls of the ridge member 22 areformed with substantially wedgeshaped recesses 25 to receive the hooks16 on the upper part 10. The lower edge of the recesses 25 are disposedat the shoulder 23, and the side face 26 of these recesses, intended toengage the end face 16a of the hooks 16, slopes slightly inwards fromthe side wall of the ridge member and away from the top side of theridge member. The rear ends of the lower part are formed with bevels 27on the underside. The upper portion of the ridge member 22 has anupwardly decreasing cross-section to ensure that the ridge member isguided correctly into the channel-shaped upper part without any tendencyof "turning over", just as the impression itself is facilitated.Preferably, the height of the ridge member 22 is at least half theheight of the entire lower part 20.

In the front portion of the lower part 20 there is embedded a metallicinsert which is shown in FIG. 5 and is generally designated by 30. Thisinsert is made of wear-resisting steel or by pressing and sintering of apowder of a metal alloy giving a hard and wear-resisting product. Theinsert consists of a plate 31 whose underside, in the finished lowerpart, is coplanar with the underside of the outer member 21 and thusforms a thread face at the point of maximum wear. In the shownembodiment the front edge of the plate 31 protrudes slightly from theside wall of the outer member 21. The top side of the plate 31 has anupwardly extending element 32 whose top is formed with a forwardlydirected, horizontal flange 33 forming, in the finished lower part, aprojection which protrudes from the front portion of the side wall ofthe ridge member 22. When the lower part 20 has been placed in positionin the upper part 10, there is only a relatively thin layer of plasticsmaterial between the rear side of the member 32 and the inner side wall12 of the upper part. The top side of the plate 31 also mounts two pins34 which are formed with heads and serve to anchor the insert in thematerial of the lower part 20.

The lower part 20 is applied to the upper part 10 nailed to the hoof byinserting the projection 33 on the lower part into the recess 18 in theupper part, the lower part being kept inclined with respect to the upperpart, and then the horse is allowed to tread on the shoe so that theridge member 22 of the lower part is progressively pressed up into thechannel 15 of the upper part. This pressing movement causes the ridgemember 22 to be deformed by the projecting hooks 16 on the side walls 12and 13 of the upper part. As the ridge member is pressed into position,first the front portion and finally the rear portions, the hooks 16 snapinto the corresponding recesses 25 in the side walls of the ridgemember, causing the end face 16a of the hooks to engage the justslightly inclined side faces 26 of the recesses 25. This engagementforms a locking engagement which cannot be released by the influencesthe horseshoe will experience even under extreme conditions such asjumping and difficult terrain.

The lower part is removed by inserting a hoof cleaner or a similar tool,e.g. a screwdriver, between the rear end wall on one fork of the upperpart 10 and the lower part 20 and tiltingit about the edge of the wall.The lever or crowbar effect thus provided produces a sufficient force toovercome the resistance offered by the rear end of the side face 26 inthe closest recess 25 against yielding elastically to the pressure fromthe end face 16a of the corresponding hook 16. Once this resistance hasbeen overcome, the rear end portion of the lower part can be released byrolling-off movement as the edge of the recess point by point slidesover the hook edge with elastic deformation of the material around therecess. When the end portion in question of the lower part has thuscleared the upper part, the other recesses in the fork in question canbe released one by one from their hooks by rolling-off movements likethe one described in the foregoing, so that the entire fork is graduallyreleased. Then the same process is repeated with the other fork of thelower part, and once this fork too has been released, the forwardlydirected projection 33 can be pulled out of the recess 18. The removalhas thus been completed, and another lower part can be applied.

When a horse gallops it may happen that the rear hooves hit the fronthooves. This might conceivably provide precisely the action on the rearends of the lower parts on the front hooves of the horse which isrequired for the lower part to be removed. Such influence, however, isprevented by the bevels 27.

In the underside of the lower part 20 there may in a known manner beembedded spikes (not shown) for use on an icy surface or calks for useon a soft surface or other forms of anti-slippage means.

The embodiment of the horseshoe of the invention which is shown in FIGS.6-10 differs from the one shown in FIGS. 1-5 and described in theforegoing only in the structure of the locking means and the rear endsof the two parts and in the provision of two oblong recesses 24a insteadof individual recesses 24 for nail heads in each fork. The samereference numerals are used in FIGS. 6-10 as in FIGS. 1-4 forcorresponding parts which are the same in the two embodiments.

The outer member 21 of the lower part 20 shown in FIGS. 8 and 9 hasrearwardly an end portion 49 instead of a bevel; the end portion 49 issomewhat narrower than the rest of the outer member and is softlyrounded and slopes rearwardly. Moreover, in a rearwardly extending endface of the ridge member 22 there is formed a groove 28 which isrelatively wide and low and extends in the entire height of the ridgemember. Further, the rear end wall of the upper part is a little lowerthan the side walls of the channel as shown at 48 in FIG. 7.

The depression or cut 48, which is formed by the lower channel end wall,facilitates the introduction of a hoof cleaner or other tool between theupper part and the lower part to remove the second, and the furtherintroduction is additionally facilitated in that the groove 28 serves asa guide for the tool.

The insert, which is shown in FIG. 10, is generally designated by 40 andconsists of a plate 41 forming a wear bracket in the toe portion of thelower part 20. The top side of the plate 40 mounts a punched and bentbridge member 42, which is formed of a metal plate and has two end lugs46 welded to the plate 41. In the centre of its front edge the bridgemember moreover has a forwardly directed locking hook 43 which issupported by an angularly bent bridge member portion 44 welded to theplate 41. The bridge member is also supported and stiffened by anangularly bent portion 45 welded to the plate 41, at the central portionof its rear edge. The bridge member 42 is moreover formed with holes 47serving to improve the anchoring of the insert in the material of thelower part.

As shown in FIGS. 6 and 7 the central portion of the outer side wall 13of the upper part 10 is here formed with a projection 19, which is bentrearwardly into the channel formed by the upper part and forms a lockinghook for cooperation with the locking hook 43 of the insert 40. In thefront portion of the ridge member of the lower part 20 there is anangular recess 29 in whose one leg, which is parallel with the top sideof the ridge member, the locking hook 43 of the insert is so disposedthat, after the other leg of the recess, which is perpendicular to andterminates in the top side of the ridge member, has been passed downover the locking hook 19 of the upper part, the locking hook 43 can becaused to overlap the locking hook 19 by rotation of the lower part withrespect to the upper part. In this position of overlap the edge hooks 16of the upper part are in register with the recesses 25 in the ridgemember 22 of the lower part, and the lower part can thus be pressed intoposition in the upper part; the engagement of the hooks 16 in therecesses 25 locks the two locking hooks 19 and 43 in the position ofoverlap by preventing such rotation of the lower part with respect tothe upper part as is required to urge the locking hooks apart from theposition of overlap. In this position the lower part is firmly fixed onthe upper part.

The outer member 21 on the lower part 20, whose rear portion is shown inFIG. 11, is formed in the same manner as the one shown in FIGS. 8 and 9with a rearwardly narrowing and inclined end portion 49. The top portionof the ridge member 22, however, is formed with inclined side faces 50,as shown in FIG. 12 too, to facilitate introduction of the ridge memberinto the channel-shaped upper part. Moreover, the regions of the sidefaces of the ridge member which are disposed between a recess 25a toreceive a hook 16 on the upper part and the upper edge of the ridgemember, are formed with longitudinal grooves 51 which further facilitatethe application of the lower part because the ridge member need only bepressed manually so deep into the channel of the upper part that atleast one hook on each fork enters one of the grooves 51 opposite thecorresponding recess 25a. This engagement is sufficient to keep thelower part in position until the horse presses the ridge member right upin the upper part by treading on the shoe. The structure shown in FIG.11 further differs from the one of FIGS. 8 and 9 in that its groove 28is here replaced by a depression 28a forming a cavity in the rear end ofeach fork.

The ridge member of the lower part may be secured in the upper partusing special nails instead of or in addition to the edge hooks 16 onthe upper part, said special nails cooperating with recesses in the topside of the ridge member as shown in FIGS. 13 and 14 in two variousembodiments.

In FIG. 13 the nail is generally designated by 52, its head by 54 andits shank by 53. Both the head and the shank are rectangular incross-section with the greatest dimension in a direction perpendicularto the plane of the paper. The head 54 is pagoda-shaped so that theuppermost part forms an annular hook 55 which, in co-operation with anengagement face 56 provided by a recess 57 in the ridge member 22produces a locking effect similar to the effect of the hooks 16 and therecesses 25 in the horseshoes described previously. The head on the nailof FIG. 14 has a frustoconical end portion 58 which is separated from abox-shaped inner portion 60 by an annular, protruding flange 59. Theflange 59 provides the intended locking effect in cooperation with anannular groove 61 which is part of a recess 62 formed in the ridgemember 22 to receive the nail head.

The locking effect provided by nails such as those shown in FIGS. 13 and14 can also be obtained by means of projections which are secured to thebottom of the channel formed by the upper part and have the same shapeas the nail heads or a shape similar thereto.

The edge hooks 16 on the upper part 10 may be produced in the mannerschematically shown in FIGS. 15-18. The upper part 10 is preformed withprojections 63 on the edges of the side walls 12 and 13. During thefirst phase of this process the projections are bent inwardly through anangle of about 45°. This closure is effected by means of the pressingtool which is shown in FIGS. 15 and 16 and is generally designated by70. The tool is a sandwich of three tempered steel plates, the centralone 71 of which has in its lower edge a trapezoidal cut whose twoinclined edges 72 form an angle with the recessed portions of the loweredge and are spaced from each other such that, when the tool is presseddown over the upper part, they bring about the desired bending of theprojections 63. The two outermost plates 73 of the tool 70 have a widthcorresponding to the distance between the side walls 12 and 13 of theupper part and protrude such a distance below the central plate 71 thatit can serve as a guide during the pressing operation. The portions ofthe edges of the outer plates disposed opposite the inclined edges 72also serve as antibackup means for the side walls of the upper part toprevent the wall portions which adjoin the ends of the projections 63from being pressed into the channel. It has been found that the risk ofruptures or cracks in the material during the pressing operation can bereduced or eliminated by providing a scratch in the side wall edges ateach side of the projection prior to the pressing operation.

After the termination of the pressing operation the upper part 10 hasthe profile shown in FIG. 17 with inwardly bent projections 63. The nextphase of the manufacturing process can be effected with a swage 75, FIG.17, which has two semi-circular cuts 76 in the lower edge, the outeredges of the cuts being spaced from each other corresponding to thespacing between the outer sides of the side walls 12 and 13 of the upperpart; the size of the cuts is so adapted that upon inward movement ofthe swage 75 over the upper part 10 and against a block-shaped anvil 77in the channel thereof they convert the projections 63 to hooks 16 witha curved top side and a plane underside 16a disposed perpendicularly tothe side wall 12 or 13 as shown in FIG. 18. In this swage forgingprocess the side walls 12 and 13 are bent slightly outwards, but enoughfor the anvil 77 to be removed without difficulty after completedoperation by manipulating a handle 78 secured on the anvil.

FIG. 19 shows an insert 80 consisting of a plate which is bent tosubstantially form a channel with a bottom 81 and two curved side walls82 and 83. The bottom 81 is welded to the top face of a wear plate heredesignated by 84. The side walls 82 and 83 are formed with inwardly bentlugs 85 and 86, respectively, serving to improve the anchoring of theinsert in the lower part. With the same end in view holes 87 areprovided both in the side walls 82 and 83 and in the lugs 85 and 86. Alongitudinal slit 88 slightly spaced from the bottom 81 is formed in thefront side wall 82, defining a free edge strip 89 of the wall 82. Partof this edge strip is bent inwardly to form a recess 90 which, under theapplication of the lower part, allows the edge strip to pass past thelocking hook 19 of the upper part so that the non-inwardly bent portion91 of the edge strip, which forms the locking hook of the insert, canthen be moved over the locking hook 19 of the upper part by rotating thelower part with respect to the upper part to lock the two parts.Provided that the edge strip 89 has a reasonable width this embodimentis able to retain the lower part on the upper part against greaterforces than the one shown in FIG. 19.

When the lower part is provided with calks it may be desirable underparticularly severe conditions, e.g. competitive riding, that the frontcalks which are subjected to the strongest influences are better securedthan is possible by embedding in the plastics of the lower part, alone.Such particularly effective securing can be obtained when the calk asshown in FIG. 20 extends through holes in the wear plate 84 and thebottom 81 of the channel-shaped portion 80 and engages the hole 87 inthe lug 86 with its conical end portion 93. A similar arrangementwithout the use of a wear plate is shown in FIG. 21.

To further improve the anchoring of the insert in the lower part, theinsert may be formed with various forms of projections, e.g. such awelded angle 94 with a hole 95 as is shown in FIG. 22.

The nail holes 14 in the upper parts shown in FIGS. 1, 2, 6 and 7 areproduced by punching of small, rectangular pieces of material. In theupper part embodiment shown in FIG. 23 the nail holes, here designatedby 96, are produced without punching of material, viz. by firstproducing a depression by means of a die and then pressing or hammeringa mandrel through the bottom of the depression to produce a crater-likenail hole with burr walls 97 which usually have a somewhat irregular,serrated form. Sharp edges and points on these burr walls may be removedor rounded by a subsequent treatment, e.g. by placing the upper part ina granular abrasive material in a rotary drum. Such nail holes withpressed burr walls which are beaten into the horse's hoof during shoeingpresent greater engagement faces for the nails and thus offer a morerealiable securing of the upper part. Also, such connection isestablished between the shoe and the hoof that horizontal forces on theshoe are transmitted directly to the hoof so that the shoe iseffectively prevented from being displaced on the hoof.

In practice the horseshoe of the invention may be cnstructed in otherways than those shown in the drawing and described in the foregoing. Forexample, the side walls of the upper part need not be exactlyperpendicular to the bottom wall, but may optionally be inclinedslightly inwardly to produce a dovetail-effect, or slightly outwardly tofacilitate application and removal of the lower part. Instead of theedge hooks 16 on the upper part side walls, inwardly extendingprojections may optionally be punched in these walls. The distributionand arrangement of projections and recesses may be varied in many ways.On the same horseshoe there may also be used combinations of thefeatures described in the foregoing.

I claim:
 1. In a horseshoe having a fixed, channel-shaped upper partwith a bottom wall intended for engagement with a horse's hoof and afront and rear side wall and an exchangeable lower part of an elasticmaterial, said lower part having a ridge member having side walls and atop side intended for insertion into the channel of the upper part andan exposed underside, the upper part being firmly connected to the ridgemember of the lower part by cooperating projections and recesses, theimprovement wherein the projections are provided on the upper part andhave a top side that inclines inwardly and downwardly from the edges ofthe side walls toward the bottom wall of the channel of the upper partand that terminate in a flat end face extending substantiallyperpendicular to the side wall and spaced from the bottom wall of thechannel, said projections engaging with an opposing face of acooperating recess formed in the side walls of the ridge member of thelower part, said projections snapping into the recesses upon impressionof the ridge member of the lower part into the channel of the upper partto thereby lock the parts together, and an insert of a hard, strongmaterial embedded in the toe portion of the lower part, said inserthaving a locking member which engages with a cooperating locking memberin the upper part, in which engaging position the two locking membersare fixed by said snapping of said projections into said recesses. 2.The horseshoe of claim 1, in which the insert has a portion that, in theassembled horseshoe, protrudes upwardly in front of the rear side wallof the upper part.
 3. The horseshoe of claim 1 or 2, in which thelocking member in the upper part comprises a recess in the front portionof the front wall of the upper part and the locking member in the insertcomprises a projection on the insert that engages with said recess. 4.The horseshoe of claim 1 or 2, in which the locking member in the upperpart comprises a first locking hook extending rearwardly from the frontportion of the front side wall of the upper part and the locking memberin the insert comprises a second locking hook, whereupon displacement ofthe lower part with respect to the upper part, the two locking hooks canbe caused to overlap each other, with the locking hook of the insertdisposed closest to the channel bottom of the upper part.
 5. Thehorseshoe of claim 1, in which the insert is of a wear-resistingmaterial and is so shaped that it also forms a wear bracket on thecentral portion of the underside of the lower part.
 6. The horseshoe ofclaim 1, including calks secured in the insert.
 7. The horseshoe ofclaim 1, in which the top side of the projections facing away from thebottom of the channel curves from the side wall towards the flat endface.
 8. The horseshoe of claim 1, in which longitudinal grooves areformed in the sides of the ridge member between the recesses and the topof the ridge member.
 9. The horseshoe of claim 1, in which the lowerpart has a shoulder face at the bottom of the ridge member forengagement with the edges of the side walls of the upper part, and therecesses in the side walls of the ridge member adjoin the shoulder face.10. The horseshoe of claim 1, in which the height of the ridge member isat least half the height of the lower part.
 11. The horseshoe of claim1, in which the upper portion of the ridge member has an upwardlydecreasing cross-section.
 12. The horseshoe of claim 1, in which adepression is formed in the rearwardly directed end faces of the ridgemember of the lower part, and a shallow cut is formed in the edge of therearwardly directed end walls of the upper part.
 13. The horseshoe ofclaim 1, in which the rear ends of the underside of the lower part arerounded and slope rearwardly.
 14. The horseshoe of claim 1, including anail for securing the upper part of the horseshoe to a horse's hoof,said nail having a shank and a head and formed with a shoulder face atleast along part of its periphery, said shoulder face being directedtowards and spaced from the nail shank.
 15. The horseshoe of claim 14,in which the nail has a cross-sectionally retangular head and theshoulder face is on two opposite wide sides of the nail head.
 16. Thehorseshoe of claim 14, in which each shoulder face of the nail is formedby a cut with a substantially triangular cross-section in the side ofthe nail head.
 17. The horseshoe of claim 14, in which each shoulderface of the nail is formed by a bead on the side of the nail head. 18.The horseshoe of claim 14, in which the outer end portion of the nailhead defined by the shoulder face is frustoconical in shape.
 19. Thehorseshoe of claim 14, in which the top side of the lower part is formedwith recesses to receive the nails, and these recesses have a face thatengages the shoulder face of the nail head.